Conventional electronic devices use power sources to provide electrical power to the devices. For example, the devices can use batteries as a power source. The use of battery power can be required as a result of the limitations on the availability of power from a central supplier (e.g., such as supplied through wall outlets), because of capacity limitations, such as a restriction on the number of available outlets, or as a consequence of the cost of cabling. Battery power can also be required in devices demanding mobility such as cellular telephones. In other cases, the power requirements for certain electrical devices can be so small that battery power is the most convenient or economic alternative for powering the devices. Such considerations provide the basis for many battery powered devices such as clocks, alarms, signs, computers, cell phones, and other digital devices.
In high engagement devices (e.g., devices used by only one or a few individuals, such as a laptop computers or cellular telephones), the batteries must be replaced and/or changed when the power level of the batteries reaches a relatively low level. In high engagement devices a user or users are likely to be aware of a low power condition of the batteries and take responsibility for replacing the batteries as needed. Low engagement devices (e.g., signs, fire alarms) are devices with which the users have less intimate contact. As a result of having somewhat remote contact with the devices, the users are less likely to take initiative to change batteries of the devices even when the batteries are due to be replaced.
One type of prior art battery is a smart battery formed of a power source and a processor. The smart battery is equipped to perform measurements of temperature, output, and discharge usage, of the battery itself, and to store that information in accessible storage locations. Devices using smart batteries read the measurement information from those storage locations and use the information to manage battery usage. For example, a laptop computer using a smart battery can be configured to read the battery type, power output or temperature from the processor of the smart battery. The laptop, by processing that information, can take actions such as reporting the remaining battery life to the laptop user, shutting down the laptop computer if power becomes low, or turning on a fan to cool the battery.